Quick test to compare Ruby 2.0.0-rc1 with 1.9.3p286.
I ran each command 5 times on each version. I'm using Seesaw's API in my tests.
$ time bundle exec rake environment
bundle exec rake environment 4.34s user 0.80s system 99% cpu 5.151 total
bundle exec rake environment 4.28s user 0.79s system 99% cpu 5.086 total
bundle exec rake environment 4.26s user 0.79s system 99% cpu 5.066 total
bundle exec rake environment 4.28s user 0.80s system 99% cpu 5.101 total
bundle exec rake environment 4.34s user 0.81s system 99% cpu 5.167 total
Average: 5.1142 seconds
$ time bundle exec rake environment
bundle exec rake environment 7.75s user 1.19s system 93% cpu 9.522 total
bundle exec rake environment 7.35s user 0.96s system 99% cpu 8.318 total
bundle exec rake environment 7.26s user 0.93s system 99% cpu 8.206 total
bundle exec rake environment 7.36s user 0.89s system 99% cpu 8.262 total
bundle exec rake environment 7.31s user 0.85s system 99% cpu 8.176 total
Average: 8.4968 seconds
Ruby 2.0.0-rc1 is on average 3.4826 seconds faster than Ruby 1.9.3p286 when booting the Seesaw API Rails app.
$ time bundle exec rake
bundle exec rake 49.00s user 3.40s system 87% cpu 59.965 total
bundle exec rake 49.95s user 3.55s system 87% cpu 1:01.17 total
bundle exec rake 48.09s user 3.33s system 87% cpu 58.916 total
bundle exec rake 47.60s user 3.27s system 87% cpu 58.217 total
bundle exec rake 47.48s user 3.18s system 87% cpu 57.972 total
Average: 59.248 seconds
$ time bundle exec rake
bundle exec rake 64.30s user 3.73s system 89% cpu 1:15.93 total
bundle exec rake 63.10s user 3.62s system 90% cpu 1:14.03 total
bundle exec rake 63.77s user 3.75s system 90% cpu 1:14.90 total
bundle exec rake 62.18s user 3.47s system 90% cpu 1:12.94 total
bundle exec rake 66.00s user 3.82s system 90% cpu 1:17.33 total
Average: 75.026 seconds
Ruby 2.0.0-rc1 is on average 15.778 seconds faster than Ruby 1.9.3p286 when running the Seesaw API Rails app test suite.
It's worth noting that no code changes were necessary to keep all of the tests passing.